Waterlogging
WATER LOGGING AND SALINITY PROBLEMS AND ROLE OF NGOS
M. H. Panhwar
The water logging and salinity problem is highly complex, when it comes to actual execution in the field. In general the main factors involved in water logging and salinity control need highly to chronological efforts for the success of programme.
Causes of Water Logging.
Water logging is caused by rising water table and this in turn is mainly caused by irrigation. Irrigation waters invariably contain some amount of salts, which seep unto ground and create serious problems in the future. If the quantum of irrigation water applied is so small, i.e., only meets evaporation as well as evapotranspiration requirements of crops, salts in irrigation water will remain in the soil because evaporation and evapotraspiration processes essentially are vaporization of water and vapours do not carry any salts form water into the atmospheres.
Salinity.
The river Indus water contain 150 to 250 parts per million (ppm) parts of salts at different times of the year. If annual irrigation dose of water with 150 ppm amounts to a column of 60 inches or 5 feet or about 1.5 meters, salts built up will be 3,260 cubic feet per acre in the top 3-4 feet of soil. These salts will make the land totally unproductive within 3-4 years, unless they are removed.
How farmer ever comes salinity. n In actual practice the farmer knows the problem and puts approximately 37% more water to leach down the salts out of the root zone. Addition of these salts to water table increases salinity of ground water. If ground water is used again and again and allowing 37% to seep back in to the ground, within a period of time ground water in turn will become unsuitable for further irrigation. n To overcome this problems, whenever ground water is used it is advisable to mix it with surface water to keep the salinity down. n But yet a stage is bound to come when ground water will turn unusable. Luckily for us ground water column is many
M. H. Panhwar
The water logging and salinity problem is highly complex, when it comes to actual execution in the field. In general the main factors involved in water logging and salinity control need highly to chronological efforts for the success of programme.
Causes of Water Logging.
Water logging is caused by rising water table and this in turn is mainly caused by irrigation. Irrigation waters invariably contain some amount of salts, which seep unto ground and create serious problems in the future. If the quantum of irrigation water applied is so small, i.e., only meets evaporation as well as evapotranspiration requirements of crops, salts in irrigation water will remain in the soil because evaporation and evapotraspiration processes essentially are vaporization of water and vapours do not carry any salts form water into the atmospheres.
Salinity.
The river Indus water contain 150 to 250 parts per million (ppm) parts of salts at different times of the year. If annual irrigation dose of water with 150 ppm amounts to a column of 60 inches or 5 feet or about 1.5 meters, salts built up will be 3,260 cubic feet per acre in the top 3-4 feet of soil. These salts will make the land totally unproductive within 3-4 years, unless they are removed.
How farmer ever comes salinity. n In actual practice the farmer knows the problem and puts approximately 37% more water to leach down the salts out of the root zone. Addition of these salts to water table increases salinity of ground water. If ground water is used again and again and allowing 37% to seep back in to the ground, within a period of time ground water in turn will become unsuitable for further irrigation. n To overcome this problems, whenever ground water is used it is advisable to mix it with surface water to keep the salinity down. n But yet a stage is bound to come when ground water will turn unusable. Luckily for us ground water column is many